Many commercial driving ranges at which golfers may practice their shots use artificial turf instead of real grass turf. This is done largely because maintaining real grass turf at a driving range is extremely difficult and costly. This is because many golf shots, particularly iron shots, involve the golfer making a divot. Divots are pieces of the turf that are dug up and removed by the golf club head as the head passes through a trajectory to strike the ball. In a typical, well-struck golf shot, the divot is created directly in front of the location of the ball. In a “fat” type of mishit, the divot is created at least partially behind the location of the ball. In any event, divot-making is a common and frequent part of many golf shots.
It will be understood by those of skill in the art that references to “in front of” the ball mean down range or in the direction of the intended target, while “behind” the ball means away from the intended target of the shot. Put another way, “behind” the ball is the region through which the golfer takes his or her backswing, while “in front of” the ball is the region through which the golfer's club travels on the follow-through after the ball is hit.
Practice golf mats made of artificial turf do not permit a divot to form. This causes the impact between the club head and the artificial turf to be much more severe than the impact between a club head and natural grass turf. As a result, a golfer hitting golf balls off of an artificial mat will experience much higher shock in his or her hands and arms due to the larger force being transmitted from the head and shaft of the club. It is well-known that this increased force significantly increases the risk of the golfer developing tendinitis.
Artificial turf also gives false feedback to the golfer on “fat” hits. A fat hit is one in which the club head strikes the ground too early in the swing trajectory, i.e., behind the golf ball. On natural grass, an improper “fat” hit is easy to identify: a large, deep divot and an obviously bad shot. On artificial turf, however, the club head will behave quite differently. During a fat hit on artificial turf, the club head will still make solid contact with the ball due to the fact that it cannot sink into the turf below the ball. The club head will bounce off of the artificial turf and make reasonably good contact with the ball. There will be no telltale divot, and the shot is likely to appear better than it would have off of natural grass.
There have been a number of attempts to address the foregoing problems with artificial turf practice mats. These attempts fall into two general categories: (1) including some type of suspension system under the surface from which the ball is hit so that the surface will deflect downwards when the ball is struck, or (2) permitting the surface from which the ball is hit to move laterally along the ground when struck by the club.
For example, U.S. Pat. No. 4,932,663 (“the '663 patent”) discloses a golf swing practice mat that utilizes two layers of artificial turf to support the golf ball. Both layers of turf are secured independently to a frame, and the top layer is secured using elastic straps. In this design, the mat has vertical “give” and the top layer is intended to slide on top of the bottom layer to simulate the shock associated with taking a divot from the ground of a natural golf course. In one embodiment, a series of layers of green nylon netting attached to the frame using a tether. The layers of netting are intended to simulate divots when a ball is struck off of the mat.
U.S. Pat. No. 5,888,147 (“the '147 patent”) discloses a golf practice mat that includes an artificial turf “anchor piece” and an artificial turf “divot piece.” The anchor piece is secured to the ground using golf tees and is secured to the divot piece using a combination of elastic rubber bands and nylon cord. The bands and cord allow the divot piece to slide forward away from the anchor piece when a user strikes a golf ball off of the divot piece.
The systems disclosed in the '663 and '147 patents (as well as numerous other, similar systems) are purported to reduce the impact force felt by a golfer. But, the reduction in force is not enough to make the practice shots feel similar to comparable shots off of natural turf. In these systems, the club still has to transmit sufficient force to deflect the surface downward against the force of the suspension system and/or forward across the ground even on properly struck shots. Further, these systems still give inaccurate feedback on “fat” hits.
What is needed, therefore, is a mat for practicing golf shots that provides an accurate simulation of golf shots hit off of natural turf. What is also needed is mat that transmits a reduced force to the golfer that is actually similar to the force involved in a golf shot off of natural turf. What is also desired, is such a mat that is compact, lightweight, and easy and inexpensive to manufacture and maintain.